Flapper valve



R. B. WATROU S FLAPPER VALVE Aug. 30, 1960 Filed Dec. 3, 1954 FIG.

FIG. 3

INVENTOR 7 ROBERT B. WATROUS ATTOR N EY Patented Aug. 30, 1960 FLAPPERVALVE Robert B. Watrous, Philadelphia, Pa., assignor toMinneapolis-Honeywell Regulator Company, Minneapolis, Minn., acorporation of Delaware Filed Dec. 3, 1954, Ser. No. 472,865

7 Claims. (Cl. 137-82) The primary object of the present invention is toprovide a thin resilient flapper valve of novel type for use in controlapparatus, and particularly control apparatus regulating the pressure ofa compressible fluid in a pressure chamber by variably throttling ableed orifice or outlet from said chamber. More specifically, theinvention is characterized by the novel form of the flapper valve andthe manner in which it is adjusted to regulate the throttling efiectimpressed on the bleed orifice.

The flapper valve may be in the form of a plastic plate in some cases,but in its preferred practical form, the flapper valve is in the form ofa metallic strip having opposing ends which are compressed by a variablecompressive force, to thereby variably bow said entire strip so that thecentral portion of the strip is moved toward and away from the bleedorifice of the pressure chamber.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the inventionhowever, its advantages, and specific objects attained with its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described preferred embodimentsof the invention.

Unless otherwise noted corresponding components shown in the variousfigures carry corresponding reference characters.

Of the drawings:

Fig. l is an elevation of one embodiment of the invention;

Fig. 2 is a section on the line 22 of Fig. 1; and

Fig. 3 is an elevation of a modified form of the invention.

In the simple form of the invention shown in Figs. 1 and 2, A representsthe discharge nozzle of a pressure chamber, not shown, to which acompressible fluid is transmitted. The rate at which fluid is dischargedby the nozzle A through its discharge port a is dependent on the fluidpressure in the nozzle A, and on the distance between the discharge endof the port a and the adjacent portion of a flapper valve B. As shown inFigs. 1 and 2, the valve B is in the form of an elongated thin flexiblestrip or plate of tempered steel or other spring metal. Said valve maywell be and as shown is of a length appreciably greater than the widthof the valve, and is transverse to the axis of the orifice a. Ordinarilyeach of the two ends of the valve B are at approximately the samedistance from the orifice outlet.

In its normal operating condition shown in Figs. 1 and 2, the flappervalve B is flexed or bowed, so that the central portion of the valve isnormally relatively closer to the discharge end of the nozzle A than isthe plane bb including the end portions 1) and be: of the valve. Withthe arrangement shown in Fig. 1, the valve end portion b may well bedirectly above the valve end portion ha. The lower valve end ba is shownextending into and being received by a notch or recess c formed in theupper side of a stationary block or abutment C, while the upper end b ofthe valve B extends into a notch d formed in the under side of anormally horizontal beam D.

One end of the beam D is pivotally connected to a Stationary support E.As shown, the pivotal connection is of the well known type comprisingthin flexible metal plates F and f at right angles to one another. Asshown, the plate F is vertical and has a lower portion abutting againstand attached to the adjacent end of the beam D, and has an upper portionalongside and attached to the vertical side of the stationary supportingelement or abutment E. The plate f is horizontal and has one portionresting on and secured to the upper side of the beam D, and has-a secondportion which extends beneath and is attached to the under side of thesupport E. A vertical thrust member G, laterally displaced from themember E, bears against the upper side of the beam D and subjects thelatter to a variable load force which variably depresses the beam D, andvariably bows the central portion of the flapper valve toward the nozzleA and away from a stationary stop H. The latter may well be and as shownis in alignment with the nozzle A and at the opposite side of theflapper B from said nozzle. The stop H is spaced closely enough to thenozzle A to insure that the down movement of the beam D will move thecentral portion of the flapper B toward, and not away from, the nozzleA.

The apparatus shown diagrammatically in Figs. 1 and 2, is characterizedby its inherent capacity for an unusually high ratio of the horizontalmovement of the central portion of the flapper valve toward and awayfrom the nozzle A, relative to the vertical movement of the flappervalve end portion b toward and away from the abutment C. The flapperwill thus possess a high gain characteristic, or, in other words, anunusually high ratio of movement of its central position with respect toits minute end portion movement. As will be apparent, the apparatusshown in Figs. 1 and 2 is adapted for a variety of uses. In particular,it is adapted to increase or decrease a fluid pressure in a nozzle inaccordance with respective increasing or decreasing variations in thepressure impressed on the beam D by the thrust member G. The latter maybe actuated in various ways and for various purposes. For example, thethrust member G may be attached to a flexible diaphragm forming one wallof a variable pressure chamber. it is noted that the present inventionis well adapted as a substitute for flapper and beam elements now incommercial use in differential pressure measuring apparatus, and intransmitting apparatus which are respectively disclosed in the pendingapplication for patent of Booth, Du Bois, and West, Serial No. 248,358,filed September 6, 1951, now Patent No. 2,808,725, and in the pneumatictemperature transmitting controller disclosed in the pending applicationof Konrad H. Stokes and Robert C. Whitehead, Ir., Serial No. 347,812,filed April 9, 1953, now Patent No. 2,823,688.

The apparatus collectively shown by way of example in Figs. 1 and 2 maybe modified in various ways. One such modification is shown by way ofexample in Fig. 3, wherein a horizontal beam Da has one end supported byresilient elements F and f on a stationary support E in a manner similarto that shown for the parts F, f and E as shown in Fig. l. The beam Dalso contains a notch a." cut therein to retain the end b of the flapperB in a manner identical to the notch d of beam D which retains the endI: of the flapper B shown in Fig. 1. The lower end of the flapper c isshown mounted in a stationary block in an identical manner to that shownin Fig. 1. The second end of the beam Da is connected More specifically,

, to the horizontal diaphragm l of a diflerential pressure measuringdevice having pressure chambers J and K respectively above and belowsaid diaphragm. The

chamber J is connected by a branch pipe Li toa source;

of fluid under. one pressure on one side of the orifice n and thechamber K' is connected by a branch pipe M 'to aportion of the conduit Non the other side of the orifice n through which the fluid flows ,at adifierent pressure than is present in the branch pipe L. As shown, theconduit N includes an orifice plate n with a central orifice at n, andextending across the bore of therconduit between the, conduitconnections to the pipes L and M. Asfluid flows through the conduit N inthe direction indicated'by the associated arrow, the pressure in the'portion of the conduit N at the left of the orificepla'te tionP.parallel to the beam Da and rigidly connected to are located in *anelbow-shaped extension R of the cham the latter by an elbow element Q.The parts O and P ber K. The end of the chamber extension R nearest tothe beam section Da is sealed by an elongated bellows S which looselysurrounds the right hand end portion of the beam section P and whoseleft end is welded or otherwise attached to the beam section P. Theother endof the bellows S has a radial disc-like extension s which iswelded or otherwise attached to the end of the wall surrounding thehorizontal portion of the beam section P adjacent the beam Da. As willbe ap'parent,;the nozzle A, the flapper B and the beam Da of Fig. 3,cooperate as do'the elements A, B, and D of Fig. 1.

While, in accordance with the provisions of the statutes, I haveillustrated and described the best forms of embodimentof my inventionnow known'to me, it will be apparent to'those skilled in the artithatchanges may be made in 'the fonns of the apparatus disclosed withoutdeparting from the spirit of myinvention as set forthin the appendedclaims and that in some cases certain features of my invention may beused to advantage without a corresponding use of other features.

Having now described my invention, what as new and desire to secure byLetters Patent is:

direction to shorten the 'distance between said end portions.

4. A motion amplifying motion to pressure transducer, comprising asingle thin elongated flapper plate in a partially bowed position,said'flapper plate being supported at one end and operably positioned incooperative relation with respect to a pneumatic nozzle to regulate theback pressure to .be transmitted from said nozzle, and a motion inputmeans connected to act directly on the other end of said flapper toimpart to the entire flapper a boxing motion proportional to the inputmotion.

5. Apparatus as specified inclaim 1 wherein the said motion of. saidcentral portionmoving toward said nozzle will be of a magnitude greaterthan the motion of the ends of the plate 'overja predetermined rangewhereby a motion amplification is achieved.

6. A 'motion' amplifying flapper valve structure, coinprising a singleelongated resilient thin flat plate flapper, a compressive/force ofvarying magnitude acting directly on one of two opposite elongated endsof said flapper while thesecond end is pivoted on stationary block toflexthecenter portion of said flapper into a bowed positiontoward apneumatic bleed nozzle whensaid force is decreased, said bowing actionof said flapper being of such a character that the amount of a fluidbled from said nozzle will be decreased in an ever'increasin'gproportional manner as said center of said flapper is flexed toward saidnozzle and be increased in an ever decreasing proportional manner assaid center portion is flexed away from said nozzle to thereby alterthe-magnitude of said fluid retained within said nozzle.

7. A motion amplifying apparatus for producing a fluid pressure variablein accordance with the magnitude of an input force, comprising a nozzlemember having a pressure chamber therein, a supply fluid passing into 7said chamber and out of said member, a single elongated resilientflapper of a thin flat'metalic plate configuration operably positionedtoregulate the flow of; fluid issuing from said'nozzle and a flappersupport means for applying said'input force to flex the entire length ofsaid flapper into a bowed position toward said nozzle and into said 1. Amotion amplifying flapper valve structure opera- 7 tive to variablythrottle a fluid flowing from the bleed nozzle of a pressure chamber toalter the magnitude of the pressure ofsaid fluid within said chamber,comprisand move its'central portion transversely to'a' plane .ineludingsaid end portions.

2. Apparatus as specified in claim 1','.in'cluding a stop element inposition to compel said body to bow in one direction only.

.3. Apparatus 'asspecified in claim 1, including a beam, a stationarysupport, and a pivot aboutjwhich' said beam 1 may turn'in the directionto press the other end portion toward said support, and means forapplying a variable a force to said beam to turn the latter about saidpivot in the flowfluid issuing therefrom to increase'the pressure ofsaid supply fluid in said pressure chamber as the magnitude'of saidinput force is increased and to cause said flapper to move from'itsbowed position to a gradually diminishing bowed position away from saidnozzle to decrease the pressure of said supply fluid in said chamber.as' said magnitude of said input force is decreased.

References Cited in the file of this patent UNITED STATES PATENTS.

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o s- W.

